Historically, it has been an objective of the textile industry to produce flame retardant fabrics for a variety of end uses, including apparel and uniform fabrics. To date, these efforts have been largely focused on cellulosic (that is, cotton) fabrics, which are readily made flame retardant by the addition of phosphorous-based flame retardant chemicals. However, cotton fabrics exhibit deficiencies in terms of durability, abrasion resistance, and drying time that make them unsuitable for a number of applications, including, for example, uniform and protective garments. Users of such specialized uniform and protective fabrics expect those fabrics to be flame retardant, long-lasting, abrasion resistant, and quick-drying.
In an effort to overcome the shortcomings of 100% cotton fabrics, manufacturers have used blends of cotton and synthetic yarns to produce fabrics with improved durability and shorter drying times. However, the introduction of synthetic fibers into cellulosic fabrics makes it difficult to flame-retardant treat the fabrics. In addition to the flammability of the synthetic fibers, they are also hydrophobic and can, therefore, make it difficult for flame retardant treatments to penetrate yarn bundles. When penetration does occur, the aqueous flame retardant solutions migrate to the surface of yarn bundles more rapidly than with 100% cellulosic (i.e., cotton) fabrics. The rapid drying of cellulosic/synthetic fiber blends is well known. The differences in drying rates and fabric wet-out are the primary reasons why processes that will produce satisfactory results on 100% cotton fabrics will not produce similar results on cotton/synthetic blend fabrics, where the treatment lasts the life of the garment.
Often, it has been found that the synthetic yarns or fibers in these blends tend to melt when exposed to flame, such as from a flash fire. In melting, the synthetic polymers adhere to the skin of the wearer of the garment, causing intense discomfort to the wearer. To minimize the risk of this problem occurring, manufacturers have sought to limit the amount of synthetic material used in flame retardant fabrics (as described, for example, in U.S. Pat. No. 5,480,458 to Fleming et al.) or have used different chemical treatments to apply flame retardant chemicals to both the cellulosic and synthetic components of the fabric (as described, for example, in U.S. Pat. No. 4,732,789 to Hauser et al.).
The present disclosure describes flame retardant fabrics having a synthetic content of at least 30% and a cellulosic content of at least 45%, where the fabrics have been treated with a flame retardant chemical and/or coated with a flame retardant coating. Such fabrics exhibit excellent flame retardance, while maintaining fabric strength, flexibility, and durability. Additionally, the flame retardant chemicals and/or coatings are also durable over repeated washings (even as many as 25 washes at 140° F.). Such fabrics and treatments represent advances over the prior art technology in this field.